Scubapro MK 19 / D420 Dive Regulator System

Follow the interval in your regulator's manual, since manufacturers commonly specify an annual inspection or a set number of dives and many warranties depend on it. A regulator is life-support equipment, so service belongs with a factory-trained technician rather than being attempted at home. Have it looked at sooner than scheduled if you notice increased breathing effort, free-flow, bubbles, or water in the second stage.

Make sure the dust cap is dry and firmly seated over the first-stage inlet before the regulator goes anywhere near water, because water inside the first stage is the leading cause of internal corrosion. Rinse in fresh water without pressing the purge button, since purging while depressurized can draw water back into the second stage. Shake out the water and hang it to dry with the hoses in wide, gentle loops rather than tight bends.

Regulators travel well and are usually best carried in hand luggage where they will not be crushed or lost. A regulator holds no gas of its own, so there is nothing inherently problematic about it on an aircraft, though the airline and security screeners always have the final say. Pack it dry with the dust cap in place, in a padded regulator bag or wrapped in soft gear.

Many modern regulators are supplied as suitable for nitrox mixes up to 40 percent oxygen, which is the widely used recreational industry standard, while anything above that requires dedicated oxygen-clean equipment and procedures. Confirm what your specific regulator's manual states, and follow your nitrox training and your fill station's requirements. Never assume a regulator is oxygen-service clean simply because it looks clean or is new.

A yoke (A-clamp) fitting clamps over the tank valve and is the most common connection across much of the recreational world, while a DIN fitting screws into the valve and is standard in much of Europe and in technical diving. DIN captures the o-ring inside the threads, which many divers consider more secure, but yoke is often what rental cylinders provide. Adapters exist in both directions, so check what is used where you dive before deciding.

The octopus is your backup second stage, carried so you can share air with a buddy who is out of gas, or breathe from it yourself if your primary fails or free-flows. It is normally on a longer, brightly colored hose so it is easy to find and hand over under stress. Secure it in the triangle between your chin and the bottom of your rib cage so it is instantly accessible and not dragging through sand or coral.

Store it fully dry, out of sunlight, with the dust cap in place and the hoses in wide loops rather than tightly coiled. Avoid hanging it by the second stages for long periods, which stresses the hose fittings; laying it flat in a padded bag or hanging it by the first stage is kinder. If it has sat unused for a long stretch, have it checked before your next trip rather than assuming it is ready to dive.

Yes. The MK19 EVO first stage uses a balanced diaphragm design, and the D420 second stage uses the air-balanced Progressive Flow Control Valve. Together they deliver high, natural airflow comparable to breathing on the surface, which is why SCUBAPRO positions this system for cold-water and technical diving.

Yes. SCUBAPRO rates this system for extreme cold water. The MK19 EVO first stage has an environmentally sealed, dry ambient-pressure chamber that is built specifically for cold-water and technical diving conditions, in addition to performing in temperate and warm water.

Yes. The D420 second stage's glass-fiber reinforced nylon housing is designed to accept the LP hose connection on either the left or right side, giving divers flexibility in hose routing based on personal preference or gear configuration.

This listing pairs the D420 second stage with the MK19 EVO first stage, which has an environmentally sealed, dry ambient-pressure chamber for cold-water and technical diving. SCUBAPRO also offers the D420 second stage matched to the MK25 EVO first stage as a separate system, so confirm which first stage you need.